Containers having caps permitting pressure equalization of contents of container



Sept. 8, 1964 G. s. LEPORE 3,147,876

CONTAINERS HAVING CAPS PERMITTING PRES E EQUALIZATION OF CONT FiledMarch ENTS OF CONTAINE FIG.3.

Flea.

w w v INVENTOR GEOBRYGE S. LEPORE H IS ATTORN EYS United States PatentCONTAINERS HAVING CAPS PERMITTING PRESSURE EQUALIZATION OF CONTENTS OFCONTAINER George S. Lepore, Clifiside Park, N.J., assignor to LeverBrothers Company, New York, N.Y., a corporation of Mame Filed Mar. 24,1961, Ser. No. 98,255 4 Claims. (Cl. 21556) This invention relates toimprovements in containers or receptacles formed of resilient plasticmaterials such as polyethylene, propylene and the like, for receivingliquids such as liquid detergents, cosmetics and the like, and itrelates particularly to plastic bottles for receiving such liquidcompositions and the closures therefor.

' Resilient plastic containers or receptacles, such as bottles havingresilient walls, frequently are filled with materials at relatively hightemperatures and are stored at considerably lower temperatures or may besubjected to varying atmospheric conditions which create a substantialpressure differential between the interior of the container andatmosphere. When, for example, the pressure within the container dropssubstantially below atmospheric pressure, a flexible container tends tocollapse or at least change in shape. Likewise, if the pressure insidethe container exceeds atmospheric pressure, the container may bulge andbecause of the increased pressure therein, may leak.

The present invention relates to an improved form of closure forresilient containers or containers having resilient walls to enable thecontainer to breathe under changing pressure conditions to equalize thepressures inside and outside the containers without allowing leakage ofthe contents of the container.

More particularly, the closure for the container is provided with one ormore grooves which connect the interior of the container to theatmosphere thereby permitting air or other gas to flow from the exteriorof the container into the container or vice versa, the groove orgrooves, however, being of such dimensions that leakage of the liquidcontents of the container is prevented even when the container isdisposed with the closure below the level of the liquid in thecontainer.

It has been found that the dimensions of the groove or grooves toachieve the desired results are quite critical and should not exceedabout .003 of an inch in depth or be less than about .002 of an inchdeep. The width of the groove is less critical but for best results itshould not exceed about .005 of an inch or be less than about .002 of aninch.

For a better understanding of the present invention, reference may behad to the accompanying drawings in which:

FIGURE 1 is a perspective view of a typical flexible plastic bottlehaving a cap thereon of the type embodying the present invention.

FIGURE 2 is a view in cross-section through the cap and neck of thebottle; and

FIGURE 3 is a bottom plan view of the cap removed from the bottle.

As shown in FIGURE 1, the bottle may be of substantially any desiredshape suitable for storing and vending a liquid material, such as adetergent, a hand lotion or the like. It preferably is formed of aresilient plastic, such as, for example, polyethylene or polypropyleneor other similar, relatively inert, flexible plastic material. Thebottle 10 is provided with a threaded neck 11 for receiving aninternally-threaded closure cap 12 which may be formed of materialsimilar to the container or a more rigid material, such as polystyrene,phenol-formaldehyde resin, or the like.

Referring to FIGURE 2 of the drawings, it will be seen that the skirt 13of the cap 12 has internal threads 14 for engagement with the threads 15on the neck 11 of the bottle and is also provided with acentrally-located plug 16 of solid or hollow formation which engages inthe pouring opening in the neck of the bottle to close and seal it.Also, the cap 12 has a transversely-extending, generally annular innersurface 17 which engages the end of the neck 11 of the bottle when thecap is screwed fully on the neck. With the arrangement described, if thebottle is subjected to diiferent external and internal pressures, thebottle would tend to collapse partially or to expand partially.

In accordance with the present invention, the cap 12 is modified topermit the bottle to breathe so that the pressures inside and outside ofit are equalized. To that end, the cap 12 has one or more grooves 13formed in it extending lengthwise of the plug 16 and across the annularextending portion 17 so that the interior of the bottle is connected tothe exterior atmosphere. In the cap illustrated, three grooves 18 areprovided. Air can flow freely between the outside of the neck 11 and theskirt 13 of the closure cap to the outer end of the groove or grooves18, for the reason that the skirt and neck are spaced slightly apart anda helical passage exists between the turns of the threads on the neckand cap. While axially and radially arranged grooves 18 are illustrated,they can be arranged tangentially or at any other angle across thelaterally-extending surface 17 of the cap and spirally around the plug16, or in any other desired way. Moreover, more or fewer than threegrooves may be provided.

A critical feature of the invention is the depth of the groove orgrooves 18. The grooves are shown in exaggerated size in FIGURES 2 and3, but it has been determined that the grooves should not exceed .003 ofan inch in depth and should not be less than .002 of an inch in depth inorder to permit flow of gas or air along the grooves between the outsideand the inside of the bottle, and, at the same time, prevent the liquidcontents of the bottle from leaking when difierential pressures existbetween the interior and exterior of the bottle and the bottle isdisposed so that the pouring opening is below the level of the liquidcontents of the bottle. Tests have demonstrated that bottles of the kindembodying the invention as described herein can be filled with liquidhaving a temperature of F. and then chilled to 40 F. without causingthem to collapse. Even when the bottles are stored in an invertedcondition, leakage of the liquid is completely prevented. When the depthof the grooves is increased to .005 of an inch, leakage occurs. When thedepth of the grooves is decreased below .002 of an inch, the bottles donot leak but they tend to collapse when their contents are cooled from100 F. to 40 F.

The width of the groove or grooves 18 is preferably on the order of .005of an inch, but the width of the grooves may, if desired, correspond tothe depth of the grooves so that a groove having a depth of .002 of aninch may also have the same width. Liquid does not leak from the bottlewhen the cap is provided with grooves 18 .0025 of an inch deep and .005of an inch wide. Depending upon the viscosity of the liquid packaged inthe container, some variation in the dimensions of the grooves ispossible. With more viscous liquids, the groove sizes can be increasedand with less viscous materials, the groove dimensions should bedecreased. However, for liquids such as concentrated detergents used fordishwashing or laundering, a depth of .002 to .003 of an inch issatisfactory. The widths of the grooves do not appear to be as criticalas their depth, possibly for the reason that the cap compresses slightlywhen it is screwed onto the container thereby decreasing the dimensionsof the groove and keeping the dimensions of the groove within a criticalrange.

It will be understood that the invention is susceptible to modification.Thus, if the neck of the bottle can be molded with precision to includegrooves of the dimensions indicated above, the lip and internal surfaceof the neck may be grooved rather than the opposing surfaces of theclosure cap. Moreover, when the cap does not include a plug 16, thegrooves may be formed in the surface or surfaces of the closure capwhich engages the neck of the bottle to etfeet a seal therewith.

Accordingly, the form of the invention illustrated herein should not beconsidered as limiting and the invention should be considered aslimiting only by the terms of the following claims.

I claim:

1. A container comprising a receptacle for liquid having a resilientwall and a pouring opening surrounded by a lip, a closure cap having aportion engaging said lip for closing said opening in liquid-tightrelation, and at least one groove between said portion and said lip toallow inflow and outflow of gas therebetween when said opening is closedin liquid-tight relation by said portion, said groove being between .003of an inch and .002 of an inch deep to prevent leakage of liquidtherethrough.

2. A container for liquids comprising a receptacle for liquid having aresilient wall, and a neck containing a pouring opening, a closure capfitting on said neck, a plug on said cap engageable in said pouringopening and at least one groove between the exterior of said plug andthe interior of said neck extending lengthwise thereof and connectingthe interior of the receptacle to atmosphere outside of said receptacle,said groove being between about .003 of an inch and .002 of an inch deepto permit gas to flow into and out of said receptacle and preventleakage of liquid from said receptacle when said plug is engaged in saidpour opening.

3. A container comprising a receptacle for liquid having a resilientwall and an externally-threaded neck having a pouring opening therein, aclosure cap having internal threads for engagement with saidexternally-threaded neck and a plug engaging in said pouring opening forclosing it in leak-proof relation, said cap having at least one grooveextending lengthwise of the exterior of said plug to connect theinterior of said receptacle to atmosphere exterior of said container,said groove being between about .002 and .003 of an inch deep andbetween about .002 and .005 of an inch wide to permit llow of gas andprevent flow of liquid along said groove when said opening is closed bysaid plug.

4. A container comprising a receptacle for liquid having a resilientwall and a neck containing a pouring opening and having exterior threadsthereon; a closure cap fitting on said neck; a skirt on said cap havinginterior threads thereon engageable with said neck threads, said skirtbeing in spaced relation to said neck with a helical passage between theturns of the threads on said neck and said skirt; a plug on said capengageable in said pouring opening and at least one groove between theexterior of said plug and the interior of said neck extending lengthwisethereof and connecting the interior of the receptacle to the atmosphereoutside of said receptacle through said helical passageway, said groovebeing between about .003 of an inch and .002 of an inch deep to permitgas to flow into and out of said receptacle and prevent leakage ofliquid from said receptacle when said plug is engaged in said pouringopening.

References Cited in the file of this patent UNITED STATES PATENTS234,342 Stewart Nov. 9, 1880 1,436,645 Brown Nov. 28, 1922 2,953,272Mumford et al. Sept. 20, 1960

1. A CONTAINER COMPRISING A RECEPTACLE FOR LIQUID HAVING A RESILIENTWALL AND A POURING OPENING SURROUNDED BY A LIP, A CLOSURE CAP HAVNG APORTION ENGAGING SAID LIP FOR CLOSING SAID OPENING IN LIQUID-TIGHTRELATION, AND AT LEAST ONE GROOVE BETWEEN SAID PORTION AND SAID LIP TOALLOW INFLOW AND OUTFLOW OF GAS THEREBETWEEN WHEN SAID OPENING IS CLOSEDIN LIQUID-TIGHT RELATION BY SAID PORTION, SAID GROOVE BEING BETWEEN .003OF AN INCH AND .002 OF AN INCH DEEP TO PREVENT LEAKAGE OF LIQUIDTHERETHROUGH.